Laves phases in Mg-Al-Ca alloys and their effect on mechanical properties

Zubair, Muhammad; Felten, Markus; Hallstedt, Bengt; Vega-Paredes, Miquel; Abdellaoui, Lamya; Villoro, Ruben Bueno; Lipińska-Chwałek, Marta; Ayeb, Nadia; Springer, Hauke; Mayer, Joachim; Berkels, Benjamin; Zander, Daniela; Korte‐Kerzel, Sandra; Scheu, Christina; Zhang, Siyuan

doi:10.1016/j.matdes.2022.111470

Cited by 19 publications

(11 citation statements)

References 39 publications

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“…In case of slip transfer for plastic codeformation, the active planes are very limited in both phases with <a> dislocations moving on the basal plane of Mg and the basal and prismatic planes of the Laves phase. The dominant orientation relationships identified for other Mg-Al-Ca alloys are based on parallel, [23] and near perpendicular basal plane orientations, [29,36] with the latter observed in alloys with very similar processing and microstructure to those investigated here. This implies a strong change in slip plane orientation, where codeformation takes place, that is thought to be enabled by the formation of nonbasal dislocations in the Mg matrix as a result of the stress field of the pile-up of basal dislocations at the interface.…”

Section: Rate Dependence Of Damagesupporting

confidence: 65%

“…A protective atmosphere of argon was used to melt the raw materials in a steel crucible using a vacuum induction melting system. Mg‐4.65Al‐2.82Ca (wt% alloy) was then solidified in a copper mold as described in the study of Zubair et al [ 36 ]…”

Section: Methodsmentioning

confidence: 99%

“…A protective atmosphere of argon was used to melt the raw materials in a steel crucible using a vacuum induction melting system. Mg-4.65Al-2.82Ca (wt% alloy) was then solidified in a copper mold as described in the study of Zubair et al [36] Dog bone-shaped specimens with a 10 mm gauge length for tensile deformation were cut by spark erosion. The grinding and polishing procedure for the samples was the same as discussed comprehensively in the study of Andre et al [12] For electron back-scatter diffraction (EBSD), samples after fine polishing using diamond paste of 1 μm were electropolished using AC2 (Streuers) electrolyte.…”

Section: Sample Synthesis Deformation and Imagingmentioning

confidence: 99%

“…[5][6][7][8]13,[16][17][18] Further, the shape and connectivity of the Laves phase has also pronounced effect on the ductility and thus can influence the crack formation behavior. [36] The local orientation relationships can also be one other critical factor influencing crack formation in the Laves phase, [8,29] but are challenging to investigate in a statistical manner where the skeleton dimensions become small enough and measurements by EBSD increasingly challenging. The intermetallic strut size, volume fraction, shape, and present Laves phase can be controlled by alloy composition, cooling rate after casting, and subsequent annealing.…”

Section: Rate Dependence Of Damagementioning

confidence: 99%

“…The intermetallic strut size, volume fraction, shape, and present Laves phase can be controlled by alloy composition, cooling rate after casting, and subsequent annealing. [36] Concurrent orientation imaging by EBSD across large areas at sufficiently low acceleration voltage to successfully index the small Laves phase volumes, will rely heavily on appropriate metallographic preparation and indexation method. [12,68] Digital image correlation and surface topography analysis for (quasi) in situ experiments may additionally help to reveal the role of interfacial sliding both in and normal to the surface plane and it may be possible to integrate this data into a workflow with automated damage type analysis.…”

Section: Rate Dependence Of Damagementioning

confidence: 99%

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Determination of the Rate Dependence of Damage Formation in Metallic‐Intermetallic Mg–Al–Ca Composites at Elevated Temperature using Panoramic Image Analysis

Medghalchi,

Zubair,

Karimi

et al. 2023

Adv Eng Mater

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We study a cast Mg‐4.65Al‐2.82Ca alloy with a microstructure containing an α‐Mg matrix, reinforced with a C36 Laves phase skeleton. Such ternary alloys are targeted for elevated temperature applications in automotive engines, since they possess excellent creep properties. However, in application, the alloy may be subjected to a wide range of strain rates, and thus accelerated testing is often essential. It is, therefore, crucial to understand the effect of such rate variations. Here, we focus on their impact on damage formation. Our analysis is based on high resolution panoramic imaging using scanning electron microscopy, combined with automated damage analysis using deep learning for object detection and classification (YOLOv5). We find, that with decreasing strain rate the dominant damage mechanism for a given strain level changes: at a strain rate of 5•10‐4/s, the evolution of microcracks in the C36 Laves phase dominates damage formation. However, when the strain rate is decreased to 5•10‐6/s, interface decohesion at the α‐Mg/Laves phase interfaces becomes equally important. We also observe a change in crack orientation, indicating an increasing influence of plastic co‐deformation of the α‐Mg matrix and Laves phase. We attribute this transition in the leading damage mechanism to thermally activated processes at the interface.This article is protected by copyright. All rights reserved.

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Section: Rate Dependence Of Damagesupporting

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Section: Sample Synthesis Deformation and Imagingmentioning

confidence: 99%

Section: Rate Dependence Of Damagementioning

confidence: 99%

Section: Rate Dependence Of Damagementioning

confidence: 99%

See 3 more Smart Citations

Determination of the Rate Dependence of Damage Formation in Metallic‐Intermetallic Mg–Al–Ca Composites at Elevated Temperature using Panoramic Image Analysis

Medghalchi,

Zubair,

Karimi

et al. 2023

Adv Eng Mater

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Influence of Al and Ca on the Ductility of Mg–Al–Ca Alloys

Delis,

Huckfeldt,

Hallstedt

et al. 2023

Adv Eng Mater

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Mg and its alloys offer huge potential for lightweight applications. However, many Mg alloys suffer from limited room temperature formability. It has previously been shown that the addition of Al and Ca to Mg can improve ductility. Therefore, the aim of the present work is to systematically vary the alloying content of Al and Ca and to study their effects on the slip system activity and crystallographic texture after rolling and recrystallisation. Our results show that all investigated ternary alloys in the range of 1‐2 wt.‐% Al and 0.005‐0.5 wt.‐% Ca have an increased ductility (in the range of 10‐17 % increase compared to pure Mg), whereas the binary Mg‐Al and Mg‐Ca alloys suffer from limited ductility (10% tensile elongation) and strength (175 MPa ultimate tensile strength). Non‐basal and especially <c+a>‐slip was active in all compositions (in 15‐33% of the grains examined). Basal‐type textures were observed for all compositions, but with significantly weaker basal peak intensities for Ca‐containing samples when compared to pure Mg. The combination of activation of the <c+a> slip system and texture weakening is discussed as being responsible for the improved ductility of the ternary Mg‐Al‐Ca alloys.This article is protected by copyright. All rights reserved.

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Metallurgical Synthesis Methods for Mg-Al-Ca Scientific Model Materials

Luo,

Tanure,

Felten

et al. 2024

Metall Mater Trans A

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Further improving the mechanical and corrosion properties of Mg-based alloys requires the investigation of underlying causalities between synthesis, processing, and microstructure, ideally down to the near atomic scale. However, such investigations with high resolution characterisation techniques require model materials of exceptionally controlled chemical composition and microstructure. In this context, the Mg-Al-Ca system, being attractive for offering significant improvement of the inherent brittleness of Mg alloys, is exceptionally challenging from a metallurgical perspective due to the inclusion of components with high reactivity and vapor pressures. Here, we demonstrate the applicability of various synthesis methods from arc-melting over solution growth to diffusion couples, extending to parameters for thermomechanical processing. Suitable pathways to overcome the specific challenges of the Mg-Al-Ca system are demonstrated, as well as the persistent limitations of the current state-of-the-art metallurgical laboratory technology. Solid solution sheet or wrought materials are ideally produced by induction melting in steel crucibles and casting under elevated pressure, with intermittent annealing steps between hot rolling passes to ensure homogenous chemical composition without excessive grain growth. Composite microstructures strongly depend on the solidification rate, and special care needs to be taken with regards to crucible reactions with increasing Al concentrations. Binary intermetallic compounds can be successfully produced in bulk by a variety of techniques, but the interplay between reactivity and evaporation of the melt when both Ca and Al are present required more complex approaches such as the Bridgman method for the synthesis of ternary compounds.

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Laves phases in Mg-Al-Ca alloys and their effect on mechanical properties

Cited by 19 publications

References 39 publications

Determination of the Rate Dependence of Damage Formation in Metallic‐Intermetallic Mg–Al–Ca Composites at Elevated Temperature using Panoramic Image Analysis

Determination of the Rate Dependence of Damage Formation in Metallic‐Intermetallic Mg–Al–Ca Composites at Elevated Temperature using Panoramic Image Analysis

Influence of Al and Ca on the Ductility of Mg–Al–Ca Alloys

Metallurgical Synthesis Methods for Mg-Al-Ca Scientific Model Materials

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